linux/net/core/utils.c
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   1/*
   2 *      Generic address resultion entity
   3 *
   4 *      Authors:
   5 *      net_random Alan Cox
   6 *      net_ratelimit Andi Kleen
   7 *      in{4,6}_pton YOSHIFUJI Hideaki, Copyright (C)2006 USAGI/WIDE Project
   8 *
   9 *      Created by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
  10 *
  11 *      This program is free software; you can redistribute it and/or
  12 *      modify it under the terms of the GNU General Public License
  13 *      as published by the Free Software Foundation; either version
  14 *      2 of the License, or (at your option) any later version.
  15 */
  16
  17#include <linux/module.h>
  18#include <linux/jiffies.h>
  19#include <linux/kernel.h>
  20#include <linux/inet.h>
  21#include <linux/mm.h>
  22#include <linux/net.h>
  23#include <linux/string.h>
  24#include <linux/types.h>
  25#include <linux/percpu.h>
  26#include <linux/init.h>
  27#include <linux/ratelimit.h>
  28
  29#include <net/sock.h>
  30
  31#include <asm/byteorder.h>
  32#include <asm/system.h>
  33#include <asm/uaccess.h>
  34
  35int net_msg_warn __read_mostly = 1;
  36EXPORT_SYMBOL(net_msg_warn);
  37
  38DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
  39/*
  40 * All net warning printk()s should be guarded by this function.
  41 */
  42int net_ratelimit(void)
  43{
  44        return __ratelimit(&net_ratelimit_state);
  45}
  46EXPORT_SYMBOL(net_ratelimit);
  47
  48/*
  49 * Convert an ASCII string to binary IP.
  50 * This is outside of net/ipv4/ because various code that uses IP addresses
  51 * is otherwise not dependent on the TCP/IP stack.
  52 */
  53
  54__be32 in_aton(const char *str)
  55{
  56        unsigned long l;
  57        unsigned int val;
  58        int i;
  59
  60        l = 0;
  61        for (i = 0; i < 4; i++)
  62        {
  63                l <<= 8;
  64                if (*str != '\0')
  65                {
  66                        val = 0;
  67                        while (*str != '\0' && *str != '.' && *str != '\n')
  68                        {
  69                                val *= 10;
  70                                val += *str - '0';
  71                                str++;
  72                        }
  73                        l |= val;
  74                        if (*str != '\0')
  75                                str++;
  76                }
  77        }
  78        return htonl(l);
  79}
  80EXPORT_SYMBOL(in_aton);
  81
  82#define IN6PTON_XDIGIT          0x00010000
  83#define IN6PTON_DIGIT           0x00020000
  84#define IN6PTON_COLON_MASK      0x00700000
  85#define IN6PTON_COLON_1         0x00100000      /* single : requested */
  86#define IN6PTON_COLON_2         0x00200000      /* second : requested */
  87#define IN6PTON_COLON_1_2       0x00400000      /* :: requested */
  88#define IN6PTON_DOT             0x00800000      /* . */
  89#define IN6PTON_DELIM           0x10000000
  90#define IN6PTON_NULL            0x20000000      /* first/tail */
  91#define IN6PTON_UNKNOWN         0x40000000
  92
  93static inline int xdigit2bin(char c, int delim)
  94{
  95        int val;
  96
  97        if (c == delim || c == '\0')
  98                return IN6PTON_DELIM;
  99        if (c == ':')
 100                return IN6PTON_COLON_MASK;
 101        if (c == '.')
 102                return IN6PTON_DOT;
 103
 104        val = hex_to_bin(c);
 105        if (val >= 0)
 106                return val | IN6PTON_XDIGIT | (val < 10 ? IN6PTON_DIGIT : 0);
 107
 108        if (delim == -1)
 109                return IN6PTON_DELIM;
 110        return IN6PTON_UNKNOWN;
 111}
 112
 113int in4_pton(const char *src, int srclen,
 114             u8 *dst,
 115             int delim, const char **end)
 116{
 117        const char *s;
 118        u8 *d;
 119        u8 dbuf[4];
 120        int ret = 0;
 121        int i;
 122        int w = 0;
 123
 124        if (srclen < 0)
 125                srclen = strlen(src);
 126        s = src;
 127        d = dbuf;
 128        i = 0;
 129        while(1) {
 130                int c;
 131                c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 132                if (!(c & (IN6PTON_DIGIT | IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK))) {
 133                        goto out;
 134                }
 135                if (c & (IN6PTON_DOT | IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 136                        if (w == 0)
 137                                goto out;
 138                        *d++ = w & 0xff;
 139                        w = 0;
 140                        i++;
 141                        if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 142                                if (i != 4)
 143                                        goto out;
 144                                break;
 145                        }
 146                        goto cont;
 147                }
 148                w = (w * 10) + c;
 149                if ((w & 0xffff) > 255) {
 150                        goto out;
 151                }
 152cont:
 153                if (i >= 4)
 154                        goto out;
 155                s++;
 156                srclen--;
 157        }
 158        ret = 1;
 159        memcpy(dst, dbuf, sizeof(dbuf));
 160out:
 161        if (end)
 162                *end = s;
 163        return ret;
 164}
 165EXPORT_SYMBOL(in4_pton);
 166
 167int in6_pton(const char *src, int srclen,
 168             u8 *dst,
 169             int delim, const char **end)
 170{
 171        const char *s, *tok = NULL;
 172        u8 *d, *dc = NULL;
 173        u8 dbuf[16];
 174        int ret = 0;
 175        int i;
 176        int state = IN6PTON_COLON_1_2 | IN6PTON_XDIGIT | IN6PTON_NULL;
 177        int w = 0;
 178
 179        memset(dbuf, 0, sizeof(dbuf));
 180
 181        s = src;
 182        d = dbuf;
 183        if (srclen < 0)
 184                srclen = strlen(src);
 185
 186        while (1) {
 187                int c;
 188
 189                c = xdigit2bin(srclen > 0 ? *s : '\0', delim);
 190                if (!(c & state))
 191                        goto out;
 192                if (c & (IN6PTON_DELIM | IN6PTON_COLON_MASK)) {
 193                        /* process one 16-bit word */
 194                        if (!(state & IN6PTON_NULL)) {
 195                                *d++ = (w >> 8) & 0xff;
 196                                *d++ = w & 0xff;
 197                        }
 198                        w = 0;
 199                        if (c & IN6PTON_DELIM) {
 200                                /* We've processed last word */
 201                                break;
 202                        }
 203                        /*
 204                         * COLON_1 => XDIGIT
 205                         * COLON_2 => XDIGIT|DELIM
 206                         * COLON_1_2 => COLON_2
 207                         */
 208                        switch (state & IN6PTON_COLON_MASK) {
 209                        case IN6PTON_COLON_2:
 210                                dc = d;
 211                                state = IN6PTON_XDIGIT | IN6PTON_DELIM;
 212                                if (dc - dbuf >= sizeof(dbuf))
 213                                        state |= IN6PTON_NULL;
 214                                break;
 215                        case IN6PTON_COLON_1|IN6PTON_COLON_1_2:
 216                                state = IN6PTON_XDIGIT | IN6PTON_COLON_2;
 217                                break;
 218                        case IN6PTON_COLON_1:
 219                                state = IN6PTON_XDIGIT;
 220                                break;
 221                        case IN6PTON_COLON_1_2:
 222                                state = IN6PTON_COLON_2;
 223                                break;
 224                        default:
 225                                state = 0;
 226                        }
 227                        tok = s + 1;
 228                        goto cont;
 229                }
 230
 231                if (c & IN6PTON_DOT) {
 232                        ret = in4_pton(tok ? tok : s, srclen + (int)(s - tok), d, delim, &s);
 233                        if (ret > 0) {
 234                                d += 4;
 235                                break;
 236                        }
 237                        goto out;
 238                }
 239
 240                w = (w << 4) | (0xff & c);
 241                state = IN6PTON_COLON_1 | IN6PTON_DELIM;
 242                if (!(w & 0xf000)) {
 243                        state |= IN6PTON_XDIGIT;
 244                }
 245                if (!dc && d + 2 < dbuf + sizeof(dbuf)) {
 246                        state |= IN6PTON_COLON_1_2;
 247                        state &= ~IN6PTON_DELIM;
 248                }
 249                if (d + 2 >= dbuf + sizeof(dbuf)) {
 250                        state &= ~(IN6PTON_COLON_1|IN6PTON_COLON_1_2);
 251                }
 252cont:
 253                if ((dc && d + 4 < dbuf + sizeof(dbuf)) ||
 254                    d + 4 == dbuf + sizeof(dbuf)) {
 255                        state |= IN6PTON_DOT;
 256                }
 257                if (d >= dbuf + sizeof(dbuf)) {
 258                        state &= ~(IN6PTON_XDIGIT|IN6PTON_COLON_MASK);
 259                }
 260                s++;
 261                srclen--;
 262        }
 263
 264        i = 15; d--;
 265
 266        if (dc) {
 267                while(d >= dc)
 268                        dst[i--] = *d--;
 269                while(i >= dc - dbuf)
 270                        dst[i--] = 0;
 271                while(i >= 0)
 272                        dst[i--] = *d--;
 273        } else
 274                memcpy(dst, dbuf, sizeof(dbuf));
 275
 276        ret = 1;
 277out:
 278        if (end)
 279                *end = s;
 280        return ret;
 281}
 282EXPORT_SYMBOL(in6_pton);
 283
 284void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
 285                              __be32 from, __be32 to, int pseudohdr)
 286{
 287        __be32 diff[] = { ~from, to };
 288        if (skb->ip_summed != CHECKSUM_PARTIAL) {
 289                *sum = csum_fold(csum_partial(diff, sizeof(diff),
 290                                ~csum_unfold(*sum)));
 291                if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr)
 292                        skb->csum = ~csum_partial(diff, sizeof(diff),
 293                                                ~skb->csum);
 294        } else if (pseudohdr)
 295                *sum = ~csum_fold(csum_partial(diff, sizeof(diff),
 296                                csum_unfold(*sum)));
 297}
 298EXPORT_SYMBOL(inet_proto_csum_replace4);
 299